Johnson Matthey"s (JMAT.L) shares plunged as much as 20% on Thursday after the British chemicals company said it would put its battery materials business up for sale amid crushing competition and that its chief executive would step down next year. Additional reporting by Pushkala Aripaka in Bengaluru; Editing by Sherry Jacob-Phillips, Susan Fenton and Steve Orlofsky You have reached your article limit Register for FREE to continue using Reuters.com Free registration gives you access to: Unmatched, global, round-the-clock news Hand-picked insights that are easy to find and use Our Daily Briefing newsletter, delivering the day"s headlines right to your inbox Already registered? Sign in